Apparatus for forming images with applicator, shearing, smoothing and cleaning means

ABSTRACT

An imaging electrode assembly for forming photoelectrophoretic images in automated machines. Various components surrounding the electrodes prepare them to aid in image formation. One roller electrode is driven past an imaging suspension applying and leveling apparatus, a suspension shearing apparatus and suitable surface wipers. Another roller electrode passes cleaning brushes and wetting apparatus to remove materials picked up on its surface during its action in the photoelectrophoretic imaging machine cycle.

United States Patent Egnaczak et al.

1151 3,658,687 51 Apr. 25, 1972 APPARATUS FOR FORMING IMAGES WITHAPPLICATOR, SHEARING, SMOOTHING AND CLEANING MEANS Raymond K. Egnaczak,Williamson; Gino F. Squassoni, Pittsford, both of NY.

Assignee: Xerox Corporation, Rochester, N.Y.

Filed: Nov. 14, 1969 App1.No.: 876,641

Inventors:

u.s. c1 ..204/300 1111. c1 ...B0lk 5/02 Field of Search .204/299, 300;355/3, 4, 15, 355/17; 118/637 LX, 261, 203, 223, 224; 117/371.12,111;1o1/425,1e7

References Cited UNITED STATES PATENTS Georges et a1. ..101l167 1/1916Thornton... 8/1945 Babicz ..101/351 2,560,572 7/1951 Haywoodetal..117/111 2,987,660 6/1961 Walkup ..355/3 3,468,248 9/1969 Giori..101/425 FOREIGN PATENTS OR APPLICATIONS 938,349 10/1963 Great Britain..1 17/37 L X Primary Examiner-Winston A. Douglas Assistant Examiner-M.J. Andrews Anorney-1ames J. Ralabate, David C. Petre and Barry JayKesselman [5 7] ABSTRACT An imaging electrode assembly for formingphotoelectrophoretic images in automated machines. Various componentssurrounding the electrodes prepare them to aid in image formation. Oneroller electrode is driven past an imaging suspension applying andleveling apparatus, a suspension shearing apparatus and suitable surfacewipers. Another roller electrode passes cleaning brushes and wettingapparatus to remove materials picked up on its surface during its actionin the photoelectrophoretic imaging machine cycle.

26 Claims, 6 Drawing Figures Patented April 25, 1972 5 Sheets-Sheet lINVENTORS GI NO F. SQUASSONI RAYMOND 'K. EGN ACZAK A TTORNEY PatentedApril 25, 1972 5 Sheets-=Sheet 3 Patented April 25, 1972 3,658,687

5 Sheets-Sheet 4 Patented April 25, 1972 3,658,687

5 Sheets-Sheet 5 FIG. 6

APPARATUS FOR FORMING IMAGES WITH APPLICATOR, SHEARING, SMOOTHING ANDCLEANING MEANS This invention relates to imaging systems and morespecifically to an improved imaging electrode assembly.

Recently, a new invention was disclosed for forming black and white orfull color images through the use of photoelectrophoresis. Theinventions described in US. Pat. Nos. 3,384,488; 3,384,566 and 3,383,993disclose a system where photoelectrophoretic particles migrate in imageconfiguration providing a visual image at one or both of two electrodesbetween which the particles are placed in suspension. Thy particles arephotosensitive and apparently undergo a net change in charge polarity ora polarity alteration by interaction with one of the electrodes uponexposure to activating electromagnetic radiation. No otherphotosensitive elements or materials are required; hence, this providesa very simple and inexpensive imaging technique. Mixtures of two or moredifferently colored particles can secure various colors of images.Particles in these mixes may have overlapping or separate spectralresponse curves and are usable in subtractive color synthesis. Theparticles will migrate from one of the electrodes under the influence ofan electric field when struck with energy of a wavelength within thespectral response of the colored particles.

Apparatus has been invented to better utilizes the above process. Forexample, a continuous imaging machine was disclosed in US. Pat. No.3,427,242 depicts apparatus for utilizing the photoelectrophoreticprocess of the above patents. Copending application Ser. No. 876,976filed on Nov. 12, 1969 in the names of Raymond K. Egnaczak and Gino F.Squassoni and entitled Automated Imaging Machine is a more sophisticatedembodiment of a machine utilizing the new process to produce true colorreproductions of original documents or the like. In order to form aparticularly good image with the apparatus described therein one or moreimaging electrodes must interfere with the injecting electrode orimaging member under the proper conditions for photoelectrophoreticimaging to occur. This must be accomplished automatically and preciselywith proper components engaged for processing to be achieved.

Therefore, it is an object of this invention to improve imag' ingelectrode mechanisms.

Another object of this invention is to automatically provide imagingsuspension at the imaging member under the proper electrophoreticconditions.

Another object of this invention is to ink and clean electrodes for usein automated photoelectrophoretic imaging systems.

Yet another object of this invention is to supply imaging suspensionready for imaging between electrodes of a photoelectrophoretic imagingsystem.

These and other objects and advantages will become apparent to thoseskilled in the art after reading the following description taken inconjunction with the accompanying drawings wherein:

FIG. 1 schematically illustrates a preferred embodiment of a machine forforming photoelectrophoretic images;

FIG. 2 is a plan view partially broken away to show hidden parts of theimaging electrode assembly;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a side view, with hidden parts dotted, of the imagingelectrode module;

FIG. 5 is a side view, with hidden parts dotted, of the imagingelectrode module as viewed from the side opposite FIG. 4; and

FIG. 6 is a partially sectioned view taken along line 6-6 of FIG. 2.

The invention herein is illustrated and described in a preferredenvironment embodiment operating in conjunction with other apparatus toautomatically and continuously produce images of predetermined opticalobjects. Nevertheless, the invention need not be confined to such anembodiment and should be construed broadly within the limitations of theclaims. It may be that other processes or apparatus will be inventedhaving similar needs to those fulfilled by the apparatus described andclaimed herein and it is the intention herein to describe an inventionfor use in other apparatus than in the embodiment shown. Variousspecific apparatus is described for accomplishing a particular functionbut any equivalent structure can be substituted and still be within thescope of the invention.

OPERATION OF THE BASIC PHOTOELECTROPI-IORETIC SYSTEM A detaileddescription of the operation and theories relating to the actual imagingsystem automated by this invention and discussing the interaction of thephotoelectrophoretic particles in the suspension used for imageformation is found in the above cited patents. The imaging systemtherein described and which can be employed in the apparatus describedherein operates by producing electromagnetic radiation in imageconfiguration to which the individual photoelectrophoretic particleswithin the suspension are sensitive. The activating radiation and anelectric field across the imaging suspension combine between twoelectrodes in the imaging area. An electrode referred to as thetransparent injecting electrode is maintained electrically positiverelative to imaging electrodes interfacing with it at the imaging areaacross the photosensitive suspension. Therefore, particles within thesuspension that are negatively charged will be attracted to therelatively positive, transparent injecting electrode.

The injecting electrode is so named because it is thought to injectelectrical charges into activated photosensitive particles duringimaging. The term photosensitive for the purposes of this inventionrefers to the property of a particle which, once attracted to theinjecting electrode, will alter its polarity and migrate away from theelectrode under the influence of an applied electric field when exposedto activating electromagnetic radiation. The term suspension" may bedefined as a system having solid particles dispersed in a solid, liquidor gas. Nevertheless, the suspension used in the embodiment of thisinvention described herein is of the general type having a solidsuspended in a liquid carrier. The term imaging electrode is used todescribe that electrode which interfaces with the injecting electrodethrough the suspension and which once contacted by activatedphotosensitive particles will not inject sufficient charge into them tocause them to migrate from the imaging electrode surface. The imagingzone" or imaging area is that zone between two electrodes wherephotoelectrophoretic imaging occurs.

The particles within the suspension are generally insulating when notstruck by activating radiation within their spectral response curve. Thenegative particles come into contact with or are closely adjacent to theinjecting electrode and remain in that position under the influence ofthe applied electric field until they are exposed to activatingelectromagnetic radiation. The particles near the surface of theinjecting electrode make up the potential imaging particles for thefinal image to be reproduced thereon. When activating radiation strikesthe particles, it makes them conductive creating an electrical junctionof charge carriers which may be considered mobile in nature. Thenegative charge carriers of the electrical junction orient themselvestoward the positive injecting electrode while the positive chargecarriers move toward the imaging electrode. The negative charge carriersnear the particle-electrode interface at the injecting electrode canmove across the short distance between the particle and the surface ofthe electrode leaving the particle with a net positive charge. Thesepolarity altered, net positively charged particles are now repelled awayfrom the positive surface of the injecting electrode and are attractedto the negative surface of the imaging electrode. Accordingly, theparticles struck by activating radiation of a wavelength with which theyare sensitive, i.e., a wavelength which will cause the formation of anelectrical junction within the particles, move away from the injectingelectrode to the imaging electrode leaving behind only particles whichare not exposed to sufficient electromagnetic radiation in theirresponsive range to undergo this change.

Consequently, if all the particles in the system are sensitive to onewavelength of light or another and the system is exposed to an imagewith that wavelength of light, a positive image will be formed on thesurface of the injecting electrode by the subtraction of bound particlesfrom its surface leaving behind particles in the unexposed areas only.The polarities on the system can be reversed and imaging will occur. Thesystem may be operated with dispersions of particles which initiallytake on a net positive charge or a net negative charge.

The imaging suspension may contain one, two, three or more differentparticles of various colors having various ranges of spectral response.In a monochromatic system the particles includedin the suspension may beof any color and produce any color and the particle spectral response isrelatively immaterial as long as there is a response in some region ofthe spectrum which can be matched by a convenient radiation exposuresource. In polychromatic systems the particles may be selected so thatparticles of different colors respond to different wavelengths.

For photoelectrophoretic imaging to occur, these steps (not necessarilylisted in the sequence that they occur) take place: (1) migration of theparticles toward the injecting electrode due to the influence of thefield, (2) the generation of charge carriers within the particles whenstruck with activating radiation, (3) particle deposition on or near theinjecting electrode surface (4) phenomena associated with the forming ofan electrical junction between the particles and the injectingelectrode, (5) particle charge exchange with the injecting electrode,(6) electrophoretic migration toward the imaging elec trode, and (7)particle deposition on the imaging electrode. This leaves a positiveimage on the injecting electrode.

After the image is formed on the injecting electrode the electrode maybe brought into interface with a transfer member which has a chargepolarity opposite to that of the imaging electrode. The injectingelectrode is now maintained negative relative to the transfer member.The particles having a net negative charge will be attracted to therelatively positive transfer member. If a support material is interposedbetween the transfer member and the particle image, the particles willbe attracted to the support material. Therefore, a photographicallypositive image can be formed on any support material.

THE MACHINE COMPONENTS a layer of optically transparent glass 4overcoated with a thin optically transparent layer 5 of tin oxide orother electrically conducting material. A particular material suitablefor this electrode is available under the name of NESA glassmanufactured by Pittsburgh Plate Glass Company, Pittsburgh, Pa. Theinjecting electrode 1 is formed as a portion of a cylinder housed withinthe metal housing frame 2.

The machine shown schematically in FIG. 1 is positioned where theinjecting electrode cylinder portion is about to be rotated in apredetermined path to a cleaning station labeled A whereat a pluralityof cleaning members such as belts 6, 7 and 8 contact the conductivesurface 5 of the injecting electrode. On the opposite side of theinjecting electrode held stationary within the machine frame are lamps9, l0 and 11 juxtaposed to the belts 6, 7 and 8 respectively. Whenactivated, the lamps send flood light illumination through thetransparent injecting electrode at the contact areas between theelectrode and the cleaning belts. Each of the belts are activated by oneof the cylinders l2, l3 and 14 to contact the injecting electrode 1.These cylinders operate to press the belts against the conductivesurface of the injecting electrode in order to clean it.

The next station in the path of movement of the injecting electrode isthe imaging station B. Here, on the first pass of the injectingelectrode 1 through station B the first imaging member, the imagingelectrode 16 interfaces with the conductive surface 5 of the injectingelectrode 1.

The optical system at station'C projects an image to the imaging zonebetween the electrodes 1 and 16 at station 8. The optical system has alamp carriage l7 journaled at an axis 18 to oscillate in a pathindicated by the arrows. A document 20 is positioned at the platen 19.The lamps are shown at the start of scan position and as the injectingelectrode 1 passes through the imaging area at station B the lamps moveacross the platen l9 projecting an image at station B through suitablemirrors 21-23, a lens 24 and the transparent electrode 1.

The imaging electrode roller 16 moves in rolling interface relation withthe conductive surface 5 of the injecting elec trode '1 and functionsboth to supply suspension to the inject ing electrode and to image thatsuspension between the injecting electrode surface 5 and the surface ofthe electrode 16.

The injecting electrode continues to rotate at a constant velocitythrough a complete rotation of the predetermined path. It travelswithout interacting with any elements located around the periphery ofthe path until it again reaches station B at the imaging zone. Now,however, the injecting electrode 16 has been moved out of itsinterfacing position by operation of a cylinder 25 which lowers theelectrode 16 and the housing 26 supporting it. Further, a cylinder 27moves a carriage 28 along a horizontal path carrying with it the housing26 which supports the imaging electrode 16. Also moved in the carriage28 is a second imaging member, the imaging electrode 29 within a housing30 maintaining it. A cylinder 31 operates through aneccentric 32 toraise the housing 30 and the second imaging electrode 29 at the imagingzone at the imaging station B of the machine. The second imagingelectrode 29 moves in rolling interface with the injecting electrodesurface 5 as that surface passes through the imaging station B. At thistime the original 20 on the platen l9-is again illuminated by thescanning lamps 33 at the optical system station C. The scan issynchronized with the movement of the injecting electrode to project aflowing image in registration with the first projection and moving atthe same rate as is the surface 5 at the imaging zone.

The injecting electrode 1 then passes into the transfer station D. Atstation D is a transfer roller 40. A sheet of support material held inthe supply tray 41 is lifted therefrom and is carried through a vacuumtransport 42 to the transfer roller 40. It is gripped by a grippermechanism 43 on the transfer roller 40 and rotated to the injectingelectrode 1 passing at station D. Before the sheet '44 contacts thesurface 5 of the injecting electrode 1 it is moistened with a liquidthat will aid in transferring the particles of the suspension on thesurface 5. The wetting is accomplished by a wetting bar 45 rotated in apool of suitable wetting material held within a tank 46. Thetransfermember 40 rotates the support material 44 in rolling contactwith the surface 5 of the injecting electrode 1 under the influence of asuitable electric field causing the particles forming the image on theinjecting electrode to be transferred to the support material. Thesupport material is removed from the transfer member by picker fingers47 and a release mechanism on the grippers. Next it is carried on avacuum transport 48 to a fixing station E where it is heated orotherwise fixed to form a permanently bonded image on the supportmaterial which is then deposited in some suitable receptacle.

THE IMAGING ELECTRODE ASSEMBLY The image forming process occurs in theimaging zone at station B at the interfacing between the injectingelectrode 1 and an imaging electrode. It is at this interface that thephotoelectrophoretic pigments are brought between the injecting and theimaging electrodes for processing under an applied field and imageradiation coming from the optical system at station C.

The imaging electrode module fits between two machine frames 100 and101. The unit slides along a set of guide rails 102 and 103 by nylon orother low friction material rollers 104 and 105 mounted on the modulecarriage 28 to permit easy shuttling of the carriage back and forthalong the rails 102 and 103. Other guide rollers 106 and 107 fit intorails along the bottom machine frame 108 and are fastened along thebottom of the carriage 28 to aid in the movement of the carriagerelative to the machine frames 'and the injecting electrode.

The entire carriage 28 is shuttled back and forth by a cylinder 27mounted through a clevis mount 109 to the machine bottom frame 108. Theextreme position of the cylinder 27 movement is determined by anadjustable carriage return stop 111 which interacts with a flange 112 onthe carriage bracket 113. The carriage side walls 114 and 115 are themodule boundaries of the imaging electrode unit and have the guiderollers 104 and 105 protruding therefrom. Mounted on and actually formedas part of the carriage are the first and second electrode imaging tanks26 and 30 respectively.

Within the first imaging electrode tank is the imaging electrode 16mounted on its shaft 116 fastened at each end of the imaging tankthrough end caps 117 and 118 fitted into the tank side walls 119 and 120respectively. The first imaging tank 26 itself is broken into twosections. The first is the suspension applicator section which housesthe first imaging electrode 16 and mechanisms to apply and treat imagingsuspension to it. The tank is composed of an end and middle wall 121 and122 respectively and a bottom plate 123. The second section of the firstimaging electrode tank is the mount section which is open at its end andadapted for maintaining various connections motors and the like used inthe function of the invention.

Located in the applicator section of the first imaging electrode tankare the mechanisms necessary to form a layer of suspension on the firstimaging electrode 16 for imaging at the imaging zone. There is asuspension supplying brush 125 which is adapted to supply imagingsuspension to the roller 16 from a supply thereof held within the firstimaging tank. The imaging suspension supply brush 125 brings thesuspension from the bottom of the applicator portion of the tank 26 tothe surface of the first imaging electrode 16. The brush is mounted on ashaft 126 which is supported through bearings in the first imaging tankwalls 119 and 120.

In order to ensure that a smooth layer of suspension reaches theintersection of the first imaging electrode with the injectingelectrode, a smoothing rod such as a wound wire rod 127 is made to moveinto interface with the imaging electrode 16. The rod can be grooved,smooth, knurled or have any surface for pressing a uniform thin layer ofsuspension. The smoothing rod is mounted by two support arms 128 and 129to a pivot shaft 130 which protrudes through the arms 128 and 129 intothe side walls 119 and 120 of the first imaging electrode tank. Thepivot shaft 130 is preferably a torque tube which aids in applyinguniform force across the smoothing rod functioning with the surface ofthe first imaging electrode 16. The torque tube passes through suitablebearings extending through the tank wall 119 and joins with a crank arm131 pressed onto it.

Next in the path of rotation of the first imaging electrode 16 after thecontact with the suspension applying brush 125 and the smoothing rod 127is interaction with the shear roll 134. The reason for optionallyapplying a shear roll against the imaging suspension prior to imaging isincluded because certain imaging suspensions operate to form bettercolor images after a shear stress has been applied thereto. For adetailed explanation of the theories relative to this phenomena andalternative mechanisms usable therewith see copending application Ser.No. 764,721 filed in the name of E. Zucker on Oct. 3, 1968 and entitledImaging Process. The shear roll 134 is moved into and out of operatingrelationship with the first imaging electrode 116 as required by thefollowing mechanism. The roller is mounted on a shear roll shaft 135which in turn is held through a bearing to crank arm 137 and through asimilar bearing to a similar crank arm on the opposite end of the shaft.Greater detail for this mechanism is shown in FIG. 6. Also mountedthrough to the crank arm 137 is the torque tube 138. The drive shaft 140of the torque tube 138 slips through the bearing 139 in the crank arm137. The torque tube 138, however, is wedded to the crank arm 137 andthat is the driving mechanism to rotate the crank arm and the shear rollinto a position of contact with the first imaging electrode. The torquetube shaft passes through the tank wall through an Oilite bearing.

On the outboard side of the tank wall 120 the shaft mounts to a timingbelt pulley 142 which is driven by a timing belt 143. The pulley 142 isseparated from the torque tube shaft 138 by a bearing 144. That bearingfunctions with bearing 145 to turn the sprocket 146 for rapidly rotatingthe shear roll 134 through a chain 147 and a driven sprocket 148 mountedon the shaft of the shear roll 134. The shaft of the torque tube isprevented from moving relative to the pulley sprocket combination(142,146) by a collar 149 mounted on the extreme outboard side ot thetorque tube shaft.

The shear roll is electrically biased relative to the first imagingelectrode 16 in order to create better shearing effects as described inthe above mentioned copending application Ser. No. 764,721 but is notshown in the drawings.

A knife edge blade 150 is next in the path of movement of the firstimaging electrode 16. This contacts the first imaging electrode when theelectrode is out of imaging position. The blade 150 functions to preventimaging suspension from traveling around the path of travel of thesurface of the imagining electrode when there is no need for imagingsuspension in the machine cycle. The blade is fitted in acrank arm 151which is normally positioned to keep the blade out of contact with thefirst imaging electrode. The crank arm 151 is formed with two flanges152 and 153 which contact a torque tube 154 used for moving the knifeedge blade 150 against the surface of the first imaging electrodeuniformly. The torque tube shaft 155 passes through suitable bearingsthrough the side walls 119 and 120 of the first imaging electrode tankand at one end of the crank arm 156 which rotates the torque tube. Theknife blade edge 150 is brought into and out of contact with the firstimaging electrode surface through these connections in an operationdescribed below.

The remaining section of the first imaging electrode tank 26 maintainsthe shear roll drive motor 157 mounted to the bottom plate 123 of thefirst imaging electrode tank and connected through a drive sprocket 158to the timing belt 143 used to drive the shear roller 134.

The last component interacting with'the surface of the first imagingelectrode 116 is a squeegee blade 159 held in a block 160 that functionsto scrape off unused pigment and suspension from the first imagingelectrode 16. The block is machined down to an eccentric shaft end 161which is held in a setting arm 162 adjusted to a predetermined pressureby a screw 163 passing through a threaded receptacle in the setting arm162 and resting against a stop 164 mounted to the tank wall 119. Atension spring 165 maintains the setting arm 162 in the proper position.

Reference has been made to the surface of the first imaging electrode16. The surface 166 is formed of a material having a resistivity of 10ohms-cm. or greater that is necessary to maintain the proper electricalfield conditions for imaging at the imaging zone. The surface 166 isformed of such blocking material as Tedlar, a polyvinylfluoride film,available from 15.1. DuPont de Nemours & Co. or baryta paper or thelike. The backing for the surface material 166 is an electricallyconductive rubber-like material 167 that is capable of being deformedwhen contacting the injecting electrode in the imaging zone.

The same structure exist with the second imaging roller 29 which has ahigh resistivity surface 168 and a deformable inner core 169. Therefore,the second imaging roller 29 has an outer covering 168 of the sameblocking material as the outer covering 166 of the first imagingelectrode. The second imaging electrode is mounted on a shaft 170 whichpasses through the side wall 171 at end cap 172 and through the sidewall 173 at the end cap 174. Each of the end caps maintaining theimaging electrodes are constructed with bearings so that the shafts andthe electrodes thereon may be rotated freely in the end caps. Thefunction of the second imaging electrode is to remove unwantedbackground particles from the image formed on the injecting electrodeand to generally improve the image on the injecting electrode. It has nosuspension addition function as does the first imaging electrode.

in order to best accomplish the purposes of the second imaging electrodeit has been found beneficial to coat the surface with afluid similar to,if not exactly the same as the carrier liquid of the imaging suspension.Therefore, the brushes 175 and 176 function to remove liquid from theouter surface of the second imaging electrode. The liquid is maintainedin the bottom of the second imaging electrode tank 30. A wiper blade 177is held'in a mounting block 178 in contact with the surface 168 toremove the liquid therefrom. This prevents contaminated liquid fromentering the imaging zone. Each of the cleaning brushes 175 and 176 haveshafts 179 and 180, respectively, that pass through the side walls ofthe second imaging electrode cleaning tank 30. Mounted on the bottomplate 181 of the tank is a motor bracket 182 housing a motor 183 whichoperates to turn the cleaning brushes 175 and 176.

One of the tank walls 184 has a liquid dispenser near the top thereof.The liquid used to coat the surface 168 of the second imaging electrodeis squirted through a slot 185 running across the entire length of thewall 184. This permits fresh liquid to be added to the system for usewith the second imaging electrode. The liquid enters the slot from theinlet.187 shown in FIG. 4. I

In the operation of the imaging electrode module the carriage 28 isshuttled back and forth beneath the injecting electrode. Either thefirst imaging electrode 16 or the second imaging electrode 29 is therebypositioned for interfacing with the injecting electrode at station 8where light rays from the object are projected. This is done by raisingeither the first or second imaging electrode tanks will all of theassociated components therein. As shown in the figures, the tanks areshuttled by the cylinder 27 to a position where the first imagingelectrode will interface with the injecting electrode when the latter isat station B along its path. The first imaging electrode tank 26 israised up from its neutral downward position. This is accomplished bymeans of the cylinder 25 connected through a clevis mount to a crank arm190 which is fixably attached to a shaft 191 maintaining an eccentric192 thereon.

The first imaging electrode tank 26 being moved by the operation of thecylinder 25 in cooperation with the eccentric 192 is maintained forbalance on a second eccentric fastened on a shaft 193 also located underthe first imaging electrode tank 26. When the cylinder 25 is operated itrotates the shaft 191 through the crank arm 190. Besides lifting thetank on the eccentric 192, a chain 194 over a sprocket 195 mounted onthe shaft 191 drives another sprocket 196 rotating the shaft 193 with aneccentric thereon. This double shaft-eccentric arrangement is beneficialsince the tank contains heavy equipment at the one end, namely, thefirst imaging electrode and its associated apparatus, and heavyequipment on the other end including the shear roller motor 157. It isimportant to keep the tank balanced to prevent spillage of materialsheld within the tank and to ensure proper positioning between the firstimaging electrode and the injecting electrode.

The operation of the various associated apparatus with each of theelectrodes is accomplished by use of pneumatics although any othersuitable mechanisms such as hydraulics, electrical or mechanical meansmay be used to function in a manner similar to the functioning describedwith the apparatus shown in this preferred embodiment.

During the operation of the machine, the first imaging electrode 16 ispositioned under the imaging zone ready for operative interfacing withthe injecting electrode 1. As the injecting electrode 1 moves into thecontact area at station 8, the cylinder 25 is actuated pulling the crankarm 190 therewith and moving the eccentrics 191 and 193 to a positionwhere the first imaging tank 26 rests on the rise of the eccentrics. Theentire tank moves upward a predetermined amount to give the properinterfacing positioning between the injecting electrode surface and theimaging electrode 16. The imaging suspension is continually supplied tothe surface 166 of the first imaging electrode and the smoothing rodsends a metered amount of imaging suspension to the shear roll 134. Thesmoothing rod 127 is held at a predetermined pressure contact throughthe suspension to the electrode surface 166 by setting the torque tubeshaft 131 from a crank arm 250 held in position by a spring 251.

The shear roll mechanism is actuated by bringing the roll 134 intocontact with the suspension on the surface 166 of the first imagingelectrode. The shear torque tube 138 is mounted on the crank arm 252which, through the clevis mount 253 which secures it to a cylinder 254.When the cylinder 254 is actuated it causes the shear roller 134 toswing into contact with the first imaging electrode 16 through thelinkages described.

The knife blade edge is removed from surface contact with the imagingelectrode 16 and the now applied metered and sheared suspension is movedinto the imaging zone to selectively be deposited on the injectingelectrode 1 in image configuration. The suspension not forming part ofthe image transported away on the injecting electrode 1 moves with theimaging electrode 16 into contact with the squeegee 159 held in theblock 160. Here it is removed from the surface 166 before new imagingsuspension is applied by the application brush 125.

After the injecting electrode 1 passes through the imaging zone, thecylinder 25 is de-energized, lowering the first image electrode tank 26.The carriage shuttling cylinder 27 is now energized pulling the carriage28 and both the imaging tanks 26 and 30 to the right as viewed in FIGS.1 and 3. The cylinder stops this movement when the second imagingelectrode tank 30 is positioned to have the second imaging electrode 29directly under the imaging zone.

As the injecting electrode 1 again passes the imaging zone, the secondimaging electrode tank 30 is moved upward by actuating the cylinder 31and rotating the eccentric 211 to raise the second imaging tank on thehigh position of that eccentric. When the second imaging electrode 29moves in the imaging zone it has been sprayed with a fluid that iseither similar to, or exactly the same as, the liquid carrier of theimaging suspension. This helps to loosen the particles that should beremoved from the image held on the injecting electrode 1. Since themovement is under the same imaging conditions as existed with the firstimaging electrode 16 interface, the image on the injecting electrodesurface 3 is reinforced by removing the particles struck by theactivating radiation from the flowing image projected from the opticalsystem at station C.

As the second imaging electrode 29 rotates in its path of movement, thesurface 168 is cleaned of all residual suspension by the action of thecleaning brushes and 176. The surface is wiped clean and relatively dryby the action of the squeegee blade 177 held within the squeegee block178. The contaminated liquid removed from the surface 168 of the secondimaging electrode 29 is removed (by means not shown) from the secondimaging electrode tank 30 to be filtered or in other ways processed forreturn through the spray system in the wall 184 of the second imagingelectrode tank.

After the injecting electrode 1 passes through the imaging zone, thesecond electrode tank 30 is dropped to its rest position byde-activation of the cylinder 31. The cylinder 27 is once again actuatedso that the tanks shuttle back to their original position where theimaging cycle may be restarted.

While the first imaging electrode 16 is not in the imaging position,that is, while the cylinder 25 is de-activated, the knife blade edge 150is moved to contact the surface 166 of the first imaging electrode. Thisis done by activating the cylinder 255 moving the crank arm 156 to theright as shown in FIG. 4.

The cylinders referred to herein may be hydraulic or pneumatic or may bereplaced by electrical means such as solenoids or mechanical means suchas cams. Even combinations of the above may be used for achieving thefunctions required to fulfill the description given herein.

The required electric potential is supplied through an electricalconnector 215 and electrical contact brushes 216 which contact the shaft116 of the first imaging electrode. (The electrical source is not shownbut should be sufficient to generate between approximately 300 v. and5,000 v. at the surface of the imaging electrodes when contacting theinjecting electrode).

The apparatus around the second imaging electrode 29 is not cammed ormoved in and out of contact with the second imaging electrode 29 nor isit cycle dependent as are some of the components around the firstimaging electrode 16. Both cleaning brushes 175 and 176 maintaincontinual contact with the surface 169 of the second imaging electrode29. The squeegee 177 maintains a continuous pressure contact with thesurface 169 of the second imaging electrode and that pressure ispredetermined by adjustment of the squeegee mount 178. The desiredpressure contact setting is achieved by positioning a crank arm 220 byturning a set screw 221 and maintaining the proper position by a tensionspring 222. The crank arm 220 is connected to the eccentric shaft 223 ofthe squeegee mount 178. The shaft 179 of the cleaning brush 175 andshaft 180 of the cleaning brush 176 are mounted through bearings in eachof the side walls of the second imaging tank 30. An electrical potentialis supplied to the shaft 170 of the second imaging electrode by anelectrical connector 225 through electrical contact brushes 226.

The cleaning brushes are driven by the motor 183 through a drivingsprocket 230 which moves the chain 231 and the driven sprocket 232connected to the shaft 179 of the cleaning brush 175. Connected to asprocket coaxial with the sprocket 232 is a chain 233 which drives thesprocket 234 turning the shaft 180 of the other cleaning brush 176. Anidler 235 maintains the chain 233 on the sprockets.

Both the imaging rollers are driven by a single chain coming off themain drive system of the machine. The chain 240 drives sprocket 241 onthe first imaging electrode and sprocket 242 on the second imagingelectrode such that the electrodes move in synchronism with theinjecting electrode when there is contact between the two. An idler 243maintained on the idler arm 244 ensures that the chain 240 will not slipoff the sprockets 241 and 242. Since the sprockets, like the imagingelectrodes which they rotate move relative to each, this idler isbeneficial in maintaining the chain over suffrcient teeth of thesprocket to prevent the chain from slipping off the sprockets theydrive.

While this invention has been described with reference to the structuresdisclosed herein and while certain theories have been expressed toexplain the experimentally obtainable results obtained, it is notconfined to the details set forth; and this application is intended tocover such modifications or changes as may come within the purposes ofthe improvements or the scope of the following claims.

What is claimed is:

1. In an apparatus for forming images by means of electrophoreticparticle suspensions, including means to present activatingelectromagnetic radiation to the particle suspension and first andsecond electrodes for forming an image on one of said electrodes byexposure of suspension particles at an interface position therebetweento electromagnetic radiation and an electric field, the improvement incombination therewith including;

said second electrode being partially electrically conductive and havingthe surface thereof being movable through a predetermined path includingthe interface position with said first electrode; a tank in which saidsecond electrode is mounted for movement of its surface through theinterface position;

applicator means for supplying the electrophoretic suspension to thesecond electrode surface along the predetermined path prior to theinterface position, and

means to couple said second electrode to an electrical source capable ofsupplying an electric field between the first and second electrodes atthe interface position.

2. The apparatus of claim 1 further including drive means capable ofmoving the surface of said second electrode past said applicator meansand the interface position.

3. The apparatus of claim 1 said second electrode having operativelyassociated therewith cleaning means for removing residual suspensionfrom the second electrode surface along the predetermined pathdownstream from the interface positron.

4. The apparatus of claim 3 wherein said cleaning means includes asqueegee blade for contacting said second electrode surface.

5. The apparatus of claim 4 further including a block having saidsqueegee blade fitted therein and means attached to said block to movesaid squeegee blade relative to the surface of said second electrodesurface.

6. The apparatus of claim 4 wherein said second electrode has furtherassociated therewith a knife blade adapted for contacting the secondelectrode at a position along its path upstream from the interfaceposition.

7. The apparatus of claim 6 including a torque tube to applysubstantially uniform pressure between the knife blade and the secondelectrode surface during contact therebetween.

8. The apparatus of claim 6 further including means to move said knifeblade into and out of contact with said second electrode.

9. The apparatus of claim 1 wherein said second electrode surface hasoperatively associated therewith shearing means adapted for applyingshear forces along the path of movement of the surface upstream from theinterface position.

10. The apparatus of claim 9 including means to periodically move saidshearing means into and out of operable interfacing with said secondelectrode surface.

11. The apparatus of claim 9 including means to drive said shearingmeans independently of the movement of the second electrode.

12. The apparatus of claim 9 including means to apply substantiallyuniform pressure between said second electrode surface and said shearingmeans during contact therebetween.

13. The apparatus of claim 12 wherein the means to apply substantiallyuniform pressure includes a torque tube.

14. The apparatus of claim 1 wherein said applicator means includesrotatable means in virtual contact with the second electrode surface tocoat electrophoretic suspension materials thereon, and smoothing meansto meter the materials passing between the smoothing means and thesecond electrode surface, said smoothing means positioned downstreamfrom said applicator means relative to the movement of the secondelectrode surface.

15. The apparatus of claim 14 wherein said smoothing means is a rod.

16. The apparatus of claim 14 further including means to rotate saidsmoothing means into and out of operative interfacing with said secondelectrode surface.

l7. The apparatus of claim 16 wherein said means to rotate saidsmoothing rod includes means to apply substantially uniform pressurebetween said smoothing means and said second electrode surface.

18. The apparatus of claim 17 including means to adjust the uniformpressure between said smoothing means and said second electrode.

19. The apparatus of claim 17 wherein the means to apply substantiallyuniform pressure includes a torque tube.

20. In apparatus for forming images by means of exposing electrophoreticparticle suspensions to activating electromagnetic radiation and anelectric field, the improvement in combination therewith including;

an electrode being partially electrically conductive and having thesurface thereof being movable through a predetermined path adpated tointerface with a member at an imaging zone;

a tank in which said electrode is mounted for movement of its surfacethrough the imaging zone;

means to apply a liquid to the electrode surface upstream from theimaging zone;

means to clean the surface of said electrode, and

means to couple said electrode to an electrical source capable ofsupplying an electric field between the electrode and the member at theimaging zone.

21. The apparatus of claim 20 including drive means to move saidelectrode.

22. The apparatus of claim 20 wherein said means to clean includes atleast one cleaning member positioned within said tank to contact thesurface of said electrode.

23. The apparatus of claim 22 further including a squeegee adjustablypositioned within said tank to contact the surface of said electrodedownstream from said cleaning member.

24. The apparatus of claim 20 wherein said means to apply a liquid ishoused in a wall of said tank having an aperture therein such that theliquid is dispensed through the aperture to the electrode surfacedownstream from the imaging zone position.

25. The apparatus of claim 20 wherein said electrode is cylindricallyshaped.

26. The apparatus of claim 25 wherein said cylindrically shapedelectrode is a roller.

II I t

1. In an apparatus for forming images by means of electrophoretic particle suspensions, including means to present activating electromagnetic radiation to the particle suspension and first and second electrodes for forming an image on one of said electrodes by exposure of suspension particles at an interface position therebetween to electromagnetic radiation and an electric field, the improvement in combination therewith including; said second electrode being partially electrically conductive and having the surface thereof being movable through a predetermined path including the interface position with said first electrode; a tank in which said second electrode is mounted for movement of its surface through the interface position; applicator means for supplying the electrophoretic suspension to the second electrode surface along the predetermined path prior to the interface position, and means to couple said second electrode to an electrical source capable of supplying an electric field between the first and second electrodes at the interface position.
 2. The apparatus of claim 1 further including drive means capable of moving the surface of said second electrode past said applicator means and the interface position.
 3. The apparatus of claim 1 said second electrode having operatively associated therewith cleaning means for removiNg residual suspension from the second electrode surface along the predetermined path downstream from the interface position.
 4. The apparatus of claim 3 wherein said cleaning means includes a squeegee blade for contacting said second electrode surface.
 5. The apparatus of claim 4 further including a block having said squeegee blade fitted therein and means attached to said block to move said squeegee blade relative to the surface of said second electrode surface.
 6. The apparatus of claim 4 wherein said second electrode has further associated therewith a knife blade adapted for contacting the second electrode at a position along its path upstream from the interface position.
 7. The apparatus of claim 6 including a torque tube to apply substantially uniform pressure between the knife blade and the second electrode surface during contact therebetween.
 8. The apparatus of claim 6 further including means to move said knife blade into and out of contact with said second electrode.
 9. The apparatus of claim 1 wherein said second electrode surface has operatively associated therewith shearing means adapted for applying shear forces along the path of movement of the surface upstream from the interface position.
 10. The apparatus of claim 9 including means to periodically move said shearing means into and out of operable interfacing with said second electrode surface.
 11. The apparatus of claim 9 including means to drive said shearing means independently of the movement of the second electrode.
 12. The apparatus of claim 9 including means to apply substantially uniform pressure between said second electrode surface and said shearing means during contact therebetween.
 13. The apparatus of claim 12 wherein the means to apply substantially uniform pressure includes a torque tube.
 14. The apparatus of claim 1 wherein said applicator means includes rotatable means in virtual contact with the second electrode surface to coat electrophoretic suspension materials thereon, and smoothing means to meter the materials passing between the smoothing means and the second electrode surface, said smoothing means positioned downstream from said applicator means relative to the movement of the second electrode surface.
 15. The apparatus of claim 14 wherein said smoothing means is a rod.
 16. The apparatus of claim 14 further including means to rotate said smoothing means into and out of operative interfacing with said second electrode surface.
 17. The apparatus of claim 16 wherein said means to rotate said smoothing rod includes means to apply substantially uniform pressure between said smoothing means and said second electrode surface.
 18. The apparatus of claim 17 including means to adjust the uniform pressure between said smoothing means and said second electrode.
 19. The apparatus of claim 17 wherein the means to apply substantially uniform pressure includes a torque tube.
 20. In apparatus for forming images by means of exposing electrophoretic particle suspensions to activating electromagnetic radiation and an electric field, the improvement in combination therewith including; an electrode being partially electrically conductive and having the surface thereof being movable through a predetermined path adpated to interface with a member at an imaging zone; a tank in which said electrode is mounted for movement of its surface through the imaging zone; means to apply a liquid to the electrode surface upstream from the imaging zone; means to clean the surface of said electrode, and means to couple said electrode to an electrical source capable of supplying an electric field between the electrode and the member at the imaging zone.
 21. The apparatus of claim 20 including drive means to move said electrode.
 22. The apparatus of claim 20 wherein said means to clean includes at least one cleaning member positioned within said tank to contact the surface of said electrode.
 23. The apparatus of claim 22 further including a squeegee adjustably positioned within said tank to contact the surface of said electrode downstream from said cleaning member.
 24. The apparatus of claim 20 wherein said means to apply a liquid is housed in a wall of said tank having an aperture therein such that the liquid is dispensed through the aperture to the electrode surface downstream from the imaging zone position.
 25. The apparatus of claim 20 wherein said electrode is cylindrically shaped.
 26. The apparatus of claim 25 wherein said cylindrically shaped electrode is a roller. 